The Collaborative International Dictionary of English v.0.48:

Cerate \Ce"rate\, n. [L. ceratum, ceratm, fr. cera wax.] (Med.)
   An unctuous preparation for external application, of a
   consistence intermediate between that of an ointment and a
   plaster, so that it can be spread upon cloth without the use
   of heat, but does not melt when applied to the skin.
   [1913 Webster]

   Note: Cerate consists essentially of wax (for which resin or
         spermaceti is sometimes substituted) mixed with oil,
         lard, and various medicinal ingredients. The cerate
         (formerly called simple cerate) of the United States
         Pharmacopoeia is a mixture of three parts of white wax
         and seven parts of lard.
         [1913 Webster]

WordNet (r) 3.0 (2006):

cerate
    n 1: a hard medicated paste made of lard or oil mixed with wax
         or resin